pgsql: Fix generation of padding message before encrypting Elgamal in p

Fix generation of padding message before encrypting Elgamal in pgcrypto

fe0a0b5, which has added a stronger random source in Postgres, has
introduced a thinko when creating a padding message which gets encrypted
for Elgamal. The padding message cannot have zeros, which are replaced
by random bytes. However if pg_strong_random() failed, the message
would finish by being considered in correct shape for encryption with
zeros.

Author: Tom Lane
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/20186.1546188423@sss.pgh.pa.us
Backpatch-through: 10

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d880b208e5fcf55e3ae396d5fc5fa6639f58205f

Modified Files
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contrib/pgcrypto/pgp-pubenc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)